My online stalker: The feeling he could hurt me never went away

Stalker Callum Blake-O'Brien created numerous fake social media accounts to send women what prosecutors described as "unimaginably horrendous" messages. One teenager left "emotionally numb" by his unrelenting abuse says he "handpicked" his victims to cause maximum distress.

"When I read it, I felt really sick. It was talking about rape and torture.

"I took a screenshot. It was extremely long and in extremely graphic detail."

Gemma, not her real name, told the BBC how she got her first message from him one night in March 2017, when she was in her bedroom.

"I only read the first few lines; I couldn't read on and my parents read the rest of it.

"My mum said 'you should go to the police'. I was freaked out."

Gemma, who was then 17, initially wondered if the message was "some kind of joke".

She tried to find out who had sent it, but the communication was from an anonymous account that had been deactivated.

"By the time I read it, he had already created another account and starting sending other disturbing messages.

"The messages included one telling me I should not be afraid of dark alleyways because he preferred the daylight."

Image caption He was given a 10-year restraining order banning him from contacting any of his victims

They then started to include personal information about Gemma's family, including her father's work. One even mentioned her eye colour.

"I wrote back 'who is this?' and asked 'why are you doing this?'"

Blake-O'Brien, from Hereford, sent more abusive messages in response.

Within days, her family had reported the messages to West Mercia Police.

Though Gemma went to the police station armed with screenshots, she was disappointed by the officer's response.